I found this tidbit in an interview
If I got a site banned what is the procedure to get it re indexed?
This is boilerplate that we're sending out to some site owners as a pilot program if we detect spam, but it's the most current info:
"If you wish to be reincluded, please correct or remove all pages that are outside our quality guidelines. When you are ready, please submit a reinclusion request at
http://www.google.com/support/bin/request.py